PARIS - Paris became “the capital of the world” on Sunday as an estimated two million people took part in a rally to commemorate victims of attacks this week in the French capital.

The massive “unity” march wound its way through the city, led at the beginning by French President Francois Hollande.

Security was at the highest level possible in the city following three days of killing which saw 17 people gunned down in cold blood by militants linked with the al-Qaeda in the Arabian Peninsula (AQAP) and Islamic State (IS) groups.

Twelve of their victims lost their lives around the offices of the satirical magazine Charlie Hebdo – an atrocity which was seen as an attack on free speech.

Four Jews died in a similarly violent attack at a Kosher deli, while a Muslim was among three police officers gunned down.

The march started 25 minutes late, at 3.25pm (1425 GMT), with President Hollande standing alongside German Chancellor Angela Merkel.

But there were no complaints from the crowd, who had put up with extremely cold January temperatures as they waited patiently.

“We don’t mind if we stand still the whole time,” said Luc Dufour, a 26-year-old who had travelled from Lyon for the march.

“Thousands of us knew we had to be here, simply show how much we object to people killing each other.”

Jews, Christians, Muslims and non-believers could all be seen standing side-by-side.

Flanking Hollande and Merkel were a host of other world leaders including British Prime Minister David Cameron, Spanish Prime Minister Mariano Rajoy, EU parliament president Martin Schulz, Italian Prime Minister Matteo Renzi, and Ibrahim Boubacar Keita, the president of Mali.

Also in the front line was Israeli Prime Minister Benjamin Netanyahu, who linked arms four world leaders along from Palestinian Authority President Mahmoud Abbas.

As the stop-start procession moved forward, there were spontaneous bursts of the Marseillaise, the French national anthem.

People clapped as others chanted “We are Charlie”. As some waited to start the march two hours after it had started, there were unofficial claims that as many as two million had turned up.

It was Hollande who described France as “the capital of the world”, insisting that everybody should show their support for Charlie Hebdo.

The satirical magazine had published hugely controversial cartoons mocking the Prophet Mohammed which caused Al-Qaeda affiliated brothers Said and Cherif Kouachi to carry out the massacre at their offices on Wednesday.

They were themselves gunned down by police near Paris on Friday – the day that Amedy Coulibaly, a third militant in the same gang, was also killed after murdering four Jews in a Kosher store in Paris.

Thousands in today’s crowd carried “Je suis Charlie” banners on Sunday, along with flags of numerous countries, including France, Algeria and Israel.

Security services across the world had received intelligence that more terror attacks were “highly likely”, as a ring of steel was placed around Paris.

There were fears that Al-Qaeda and IS linked terror cells would be activated as up to 40 world leaders went to the rally, but their short work at the top of the cortege was over by 4pm (1500 GMT).

A convoy of buses, police cars and motorcycles was then seen travelling at high speed, as it took the VIPs back to the Elysee palace.

Some 2,000 police officers and 1,400 soldiers were deployed across Paris in an atmosphere described by one commander as “extremely tense”.

Interior Minister Bernard Cazeneuve said “exceptional measures” were being taken to try and prevent further attacks, including deploying snipers on roofs.

British Home Secretary Theresa May was among those who met Cazeneuve and others who, before the rally, discussed the threat posed by militants.

Both President Hollande and Netanyahu met leaders from Paris’s Jewish community, who remain in deep shock following the Kosher store atrocity.

Sydney Beuvry, 20, from Paris, said: “I am an artist myself, so freedom of expression is very important to me.”

“I am pleased to see so many people here today in support of all the victims. The people of Paris stand together against terrorism.”

Coulibaly, the gunman responsible, is believed to have shot dead a Paris policewoman the day before.

Police are still hunting his wife, Hayat Boumeddiene, who is believed to have fled to Syria before the killing spree started.

Described as “armed and dangerous”, the 26-year-old Boumeddiene is thought to have helped with the planning of the attacks.